1. Field of the Invention
This invention relates generally to magnetic latches and specifically to magnetic latches useful as tripping actuators in circuit breakers.
2. Description of the Prior Art
Magnetic latches are used as tripping actuators in circuit breakers. Typically magnetic latches store mechanical energy in a spring, for delivery when circuit breaker trip is indicated as a result of an over-current condition.
Magnetic latches can deliver many times more mechanical energy than the equivalent electrical energy required to demagnetize the magnetic latch flux path and hence release the circuit breaker trip mechanism. Magnetic latches effectively amplify and convert low electrical energy input to high mechanical energy output.
Heretofore, magnetic latches for circuit breakers, such as those used by the United States Navy in shipboard applications, have been too large for use in small, molded case circuit breakers. Moreover, known magnetic latches exhibit high flux leakage due to inadequate flux paths and are not balanced against the destabilizing effects of shock, which can be substantial in a combat environment. Furthermore, known magnetic latches, such as found in air circuit breakers used by the United States Navy in shipboard applications, have linear actuators with rectangular shafts protruding from the latch housing to act on the circuit breaker trip mechanism. This results in inefficient use of available space which is at a premium aboard ships.